Researchers said this is the first identification of a strong oral cavity carcinogen found in smokeless tobacco products.

"Our results are very important in regard to the growing use of smokeless tobacco in the world, especially among younger people who think it is a safer form of tobacco than cigarettes," said Stephen Hecht, Ph.D., who led the study. "We now have the identity of the only known strong oral carcinogen in these products."

The culprit, NNN, is one of a family of hundreds of compounds called nitrosamines capable of causing cancer.

Nitrosamines are found in a variety of foods, ranging from beer to bacon, and it forms naturally in the stomach when people eat foods containing high levels of nitrite as well.

During the study, the scientists gave rats a low dose of two forms of NNN in drinking water for 17 months in doses equivalent to about the amount a person consumes in half a tin of smokeless tobacco every day for 30 years.

All of the rats treated developed multiple oral tumors, including malignant squamous cell carcinogens. A total of 91 oral tumors were found in the rats.

Hecht told reporters at the press conference which redOrbit attended that there are ways tobacco companies could limit the NNN found in their products. He added that all brands were found to have the carcinogen, and so far there is no regulation to limit use.

"The most popular brands of smokeless tobacco that are sold in the U.S. have unacceptably high levels of this particular carcinogen," said Hecht.

The carcinogen is not found in natural tobacco, but instead is something tobacco companies add in during the process of making smokeless tobacco.

He said the levels found in smoking tobacco were not as strong as that found in smokeless tobacco, because 10 to 15 percent of the amount of tobacco are transferred into smoke while smoking a cigarette.

"Obviously, we need to decrease the levels of this material in all smokeless tobacco products - or eliminate it altogether," he said.

Hecht suggests that the U.S. Food and Drug Administration (FDA) regulate the tobacco products' levels of NNN in smokeless tobacco to decrease by 10 parts per billion.

"That would make it more consistent with the levels of nitrosamines in food products," he said.

Not all smokeless tobacco tested in the study had as high amount of NNN as U.S. companies. He said Swedish snuffs have lower levels of NNN because of their processing.

When asked at the press conference why lower levels of NNN aren't being used in the processing procedure in the U.S. yet, Hetch said "I don't know, it is the choice of the manufacturers."